Pro Tools Le no longer opens

[protoolsteve]

I recently had a new motherboard installed on my Macbook Pro. Now Pro Tools no longer works. I called Apple Care. Apple Care took me through installing Pro Tools Le under a new user name. That seemed to work.

I was then informed that it is a "settings issue" under my original user name that prevents Pro Tools Le from opening properly. I've completely uninstalled and re-installed Pro Tools Le under my original user name, but to no avail.

Please help. How do I change my settings to ensure that Pro Tools Le opens and runs properly again?

Thank you.

My System Details:
MacBook Pro 2.4GHz Intel Core 2 Duo 15"
RAM: 4 GB
Apple Mac OS X 10.4 (Tiger)

Pro Tools LE
USB Interface
Mbox 2 Mini
Pro Tools LE

[sw rec]

Might get better results posting in the MAC forum......